1. Finish the discussion on transformation
2. Introduction to classification problem:
     2.1. Bayesian setting, density estimation.
     2.2. Normal case -linear discriminant analysis
     2.3. Nearest neighbor
     2.4. Classification trees.
    2.5. Neural net work.
    2.6. Support vector machine.
    2.7. Bootstrapping.
    2.8. Others.